This invention relates to superconductor winding impregnation systems of the type that have impregnation assemblies that employ a pressure/vacuum containment vessel in order to form a more uniform and complete impregnation of the windings. The preferred material for impregnation is conventional epoxy. Systems of this type generally allow all of the available surface area of the windings to be impregnated while substantially reducing the likelihood an excessive amount of epoxy being retained which must be removed. The excess epoxy is usually removed in a manual fashion. Also, the present invention substantially reduces the likelihood of undesirable trapped gas bubbles forming during the impregnation. A superconductive winding is placed such that the winding is subjected, at various times, to vacuum and pressure and an epoxy compound is allowed to flow and, later, cure around the winding to impregnate the winding. This invention relates to certain unique containment vessel assemblies and the vacuum/pressure and epoxy handling/curing means, in association, therewith.
It is known, in superconductive winding impregnation systems, to make use of a system which includes an impregnation vessel large enough to adequately contain enough epoxy compound such that the winding can be completely submersed in the epoxy compound and the epoxy allowed to cure. In each of these cases, the size of the windings was the prohibitive factor in the impregnation of the windings because the containment vessel has to be large enough, typically 5-6' high and 2.5-3' in diameter for larger sized windings, in order to accommodate the winding. Due to the large volume of the vessel, a large amount of epoxy had to be used to insure that the winding was sufficiently covered and impregnated by the epoxy. Also, if the windings are varied in size and shape, there was a fair amount of guesswork involved in determining the amount of epoxy needed that would be adequate enough to impregnate the winding. Furthermore, because the winding was required to remain in the containment vessel so that the epoxy would adequately cure and impregnate the winding, the excess epoxy which remained on the winding, had to be manually removed, typically, by chipping. The process of chipping could possibly damage the windings. A more advantageous system, then, would be presented if such amounts of epoxy and manual removal of the epoxy were reduced.
It is also known that, when the epoxy was mixed and poured into the containment vessel or when the winding was placed in the epoxy batch, voids could form in the epoxy due to trapped residual gas. These voids, if not completely eliminated, would adversely affect the impregnation of the winding. Such a void could possibly result in a mechanical failure of the cured epoxy and may, ultimately, initiate a loss of superconductivity in the winding. Therefore, reductions in the amount of voids present in the impregnation system would also be advantageous.
It is apparent from the above that there exists a need in the art for a superconductive winding impregnation system which is efficient through simplicity of parts and uniqueness of structure, and which, at least, equals the safety characteristics of the known impregnation systems, but which at the same time substantially reduces the amount of epoxy used to adequately impregnate the windings and the likelihood of undesirable gas bubbles being trapped in the epoxy. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.